suprima gas valves

[pwalker]

suprima 30L fails to ignite. fan starts, igntion sparks but not flame. Getting 250 VDC to gas valve so assume PCB is not faulty in this case. Obviously this points to the gas valve (honeywell CVI 402550), my question is, is this a fixed range gas valve or will it require setting up on insatllation for the right mix. Anybody changed one before who might know?

any thought welcome, cheers and thanks in advance.

 

[ChrisR]

From your question, you clearly aren't competent to do it - and I'm not going to explain why.
Call someone in to check whether the gas valve is faulty and change it if necessary, which requires other work to be done.

 

[nickso]

firstly double check your findings by checking the resistance through the valve coil.....an open circuit is obviously faulty.

i agree with chris....you dont sound quite competent enough for this.

 

[pwalker]

I'm pretty sure its the valve, it is Open circuit between the two outer pins which the power goes to. There is about 1.4K between the top pin and the others (excluding earth!), but there it is open from the bottom pin to any of the others so maybe a dual coil solenoid with one faulty preventing operation. The voltage switches from 250vdc to 330vdc so am happy its getting the signal to operate it just isn't doing so.
The fixed range issue I referred to was the flow rate, I've got an intrinsically safe digital manometer for setting the supply and burner pressure, it was just the best practice for the flow rate verification on these valves I was wondering. i.e. get the pressures right and it's a fixed orifice thus flow is not adjustable or wether the flow rate is adjustable independantly.

 

[nickso]

ignore flow....set the gas pressure to whatever it says on the data badge.....probably 8-10mb on this boiler. in reality the burner pressure is the least of my concerns.

are you confident you will be able to remove the gas valve and replace it without causing a gas leak, setting the BP wrong or causing a combustion fault? remember to get this valve out you will have to remove the combustion chamber door and burner and you will disturb seals to keep the boiler room sealed. you really should be using an FGA after doing this work to be sure nothing you have done is likely to be a problem. a digital manometer is not intrinsically safe as such as you are going to have to open the test point to use it.....a minor point but valid i feel.

dont think the suprima uses 330vdc for the coil either

 

[pwalker]

I've got new o rings to replace the one on the mating faces betwwen the gas valve and the gas valve stop cock valve, and also for the gas valve to manifold face. I would leak check any seals broken after anyway. So should be no problem regards leaks. The manometer is intrisically safe itself in that it is gas approved and does not have the energy to ignite the gas itself, fair point that the test point has to be opened but would just have to be sensile with regards sources of igntion.
I was planning on getting someone to give the flue emmisions a check with an FGA on completion just to make sure everything looks ok.

I appreciate your concerns and welcome your comments and advice,

 

[Agile]

I know this will sound harsh to you but there is safety involved.

I just do not believe the last thing you have said about getting a qualified person to check the boiler with an FGA afterwards!!!

Its obvious to me that you have no intention of getting anyone in to check it in spite of the warnings we have given you.

If you really did then obviously you would get the qualified person to fit the new gas valve as well!

Tony

 

[pwalker]

I realise the combustion products need to be checked due to the nature of the fault and solution ,so wouldn't simply just not do it.
The reason I would get some one in to check the flue is because I don't have a FGA, and the work involved for the person doing the check (provided results ok) is minimal. Just because I'm thinking about doing the fix myself doesn't mean I'm not going to do something that I know requires doing.
Its a bit of a case of I can see the fault, know what the fix is, don't necessarily think that anyone who comes in is going to do anything differently.
In fairness I have'nt even decided I'm going to do it myself, if a lot of the cost would have come from diagnostics \ parts which I think is done now, the installation price might be pretty reasonable and not worth the bother of D.I.Y.ing it, so I'm not sure your comments about obviousness were quite on the mark.

 

[nickso]

hmm, tony, as usual, has automatically assumed that it is obvious that you are not going to get the combustion checked after working on it.....even though there was nothing to suggest you wouldnt. i actually dont care and was simply advising you on what you should do.

i know what intrinsically safe means but wasnt sure if you did. my comment about the test point was merely meant to make you aware of the other risks involved....you seem to be aware anyway.

you have all the seals bar the one that goes from the manifold to the case....it rarely breaks anyway.

phone around and ask for prices and see if it indeed would be a reasonable price to get the GV installed. i dont see it being a hideous price and for all the parts that have to come out and the FGA check afterwards you could treat it as its annual service.

really its all down to how confident you are yourself to complete the work safely.

 

[Soggy_weetabix]

you have all the seals bar the one that goes from the manifold to the case....it rarely breaks anyway.

Rarely is not EVER.

 

[corgiman]

if the OP wants to do it himself who are we to say he shouldnt

lets hope he is not an incompetant fool or some one will pay the price, lets hope its not too high

 

[nickso]

you have all the seals bar the one that goes from the manifold to the case....it rarely breaks anyway.

Rarely is not EVER.

thats why i wrote rarely and not never.

its a piece of foam from recollection and if you are careful it goes back in fine. if it breaks then replace it.....from what he has written so far i dont think the man is an idiot.

 

[pwalker]

I thought about the seal you mentioned nick, I have'nt seen it as I've not done anything yet. I imagine it to be that corky type stuff that gaskets are usually made from. So it could tear if it stuck to one of the surfaces. In which case I'd assume I'd be able to get a replacment/

 

[nickso]

its been a while since i put one on so i honestly cant remember what its made from.....just that it rarely breaks. they are available seperately i think.